/*
 *    This program is free software; you can redistribute it and/or modify
 *    it under the terms of the GNU General Public License as published by
 *    the Free Software Foundation; either version 2 of the License, or
 *    (at your option) any later version.
 *
 *    This program is distributed in the hope that it will be useful,
 *    but WITHOUT ANY WARRANTY; without even the implied warranty of
 *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *    GNU General Public License for more details.
 *
 *    You should have received a copy of the GNU General Public License
 *    along with this program; if not, write to the Free Software
 *    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 */

/*
 * ConnectionPanel.java
 * Copyright (C) 2005 University of Waikato, Hamilton, New Zealand
 *
 */

package weka.gui.sql;

import weka.gui.DatabaseConnectionDialog;
import weka.gui.ListSelectorDialog;
import weka.gui.sql.event.ConnectionEvent;
import weka.gui.sql.event.ConnectionListener;
import weka.gui.sql.event.HistoryChangedEvent;
import weka.gui.sql.event.HistoryChangedListener;

import java.awt.BorderLayout;
import java.awt.FlowLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.util.HashSet;
import java.util.Iterator;

import javax.swing.DefaultListModel;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JList;
import javax.swing.JOptionPane;
import javax.swing.JPanel;
import javax.swing.JTextField;
import javax.swing.event.CaretListener;
import javax.swing.event.CaretEvent;

/**
 * Enables the user to insert a database URL, plus user/password to connect to
 * this database.
 * 
 * @author FracPete (fracpete at waikato dot ac dot nz)
 * @version $Revision: 7059 $
 */
public class ConnectionPanel extends JPanel implements CaretListener {

	/** for serialization. */
	static final long serialVersionUID = 3499317023969723490L;

	/** the name of the history. */
	public final static String HISTORY_NAME = "connection";

	/** the parent frame. */
	protected JFrame m_Parent = null;

	/** the databae connection dialog. */
	protected DatabaseConnectionDialog m_DbDialog;

	/** the URL to use. */
	protected String m_URL = "";

	/** the user to use for connecting to the DB. */
	protected String m_User = "";

	/** the password to use for connecting to the DB. */
	protected String m_Password = "";

	/** the label for the URL. */
	protected JLabel m_LabelURL = new JLabel(Messages.getInstance().getString(
			"ConnectionPanel_LabelURL_JLabel_Text"));

	/** the textfield for the URL. */
	protected JTextField m_TextURL = new JTextField(40);

	/** the button for the DB-Dialog. */
	protected JButton m_ButtonDatabase = new JButton(Messages.getInstance()
			.getString("ConnectionPanel_ButtonDatabase_JButton_Text"));

	/** the button for connecting to the database. */
	protected JButton m_ButtonConnect = new JButton(Messages.getInstance()
			.getString("ConnectionPanel_ButtonConnect_JButton_Text"));

	/** the button for the history. */
	protected JButton m_ButtonHistory = new JButton(Messages.getInstance()
			.getString("ConnectionPanel_ButtonHistory_JButton_Text"));

	/** the connection listeners. */
	protected HashSet m_ConnectionListeners;

	/** the history listeners. */
	protected HashSet m_HistoryChangedListeners;

	/** for connecting to the database. */
	protected DbUtils m_DbUtils;

	/** the history of connections. */
	protected DefaultListModel m_History = new DefaultListModel();

	/**
	 * initializes the panel.
	 * 
	 * @param parent
	 *            the parent of this panel
	 */
	public ConnectionPanel(JFrame parent) {
		super();

		m_Parent = parent;
		m_ConnectionListeners = new HashSet();
		m_HistoryChangedListeners = new HashSet();

		try {
			m_DbUtils = new DbUtils();
			m_URL = m_DbUtils.getDatabaseURL();
			m_User = m_DbUtils.getUsername();
			m_Password = m_DbUtils.getPassword();
		} catch (Exception e) {
			e.printStackTrace();
			m_URL = "";
			m_User = "";
			m_Password = "";
		}

		createPanel();
	}

	/**
	 * builds the panel with all its components.
	 */
	protected void createPanel() {
		JPanel panel;
		JPanel panel2;

		setLayout(new BorderLayout());
		panel2 = new JPanel(new FlowLayout());
		add(panel2, BorderLayout.WEST);

		// label
		m_LabelURL.setLabelFor(m_ButtonDatabase);
		m_LabelURL.setDisplayedMnemonic('U');
		panel2.add(m_LabelURL);

		// editfield
		m_TextURL.setText(m_URL);
		m_TextURL.addCaretListener(this);
		panel2.add(m_TextURL);

		// buttons
		panel = new JPanel(new FlowLayout());
		panel2.add(panel);

		m_ButtonDatabase.setMnemonic('s');
		m_ButtonDatabase.addActionListener(new ActionListener() {
			public void actionPerformed(ActionEvent e) {
				showDialog();
			}
		});
		panel.add(m_ButtonDatabase);

		m_ButtonConnect.setMnemonic('n');
		m_ButtonConnect.addActionListener(new ActionListener() {
			public void actionPerformed(ActionEvent e) {
				connect();
			}
		});
		panel.add(m_ButtonConnect);

		m_ButtonHistory.addActionListener(new ActionListener() {
			public void actionPerformed(ActionEvent e) {
				showHistory();
			}
		});
		panel.add(m_ButtonHistory);

		setButtons();
	}

	/**
	 * sets the buttons according to the connected-state.
	 */
	protected void setButtons() {
		boolean isEmpty;

		isEmpty = m_TextURL.getText().equals("");

		m_ButtonConnect.setEnabled(!isEmpty);
		m_ButtonDatabase.setEnabled(!isEmpty);
		m_ButtonHistory.setEnabled(m_History.size() > 0);
	}

	/**
	 * sets the parameters back to standard.
	 */
	public void clear() {
		setURL(m_DbUtils.getDatabaseURL());
		setUser(m_DbUtils.getUsername());
		setPassword(m_DbUtils.getPassword());
	}

	/**
	 * sets the focus in a designated control.
	 */
	public void setFocus() {
		m_TextURL.requestFocus();
	}

	/**
	 * sets the URL.
	 * 
	 * @param url
	 *            the new value of the URL
	 */
	public void setURL(String url) {
		m_URL = url;
		m_TextURL.setText(url);
	}

	/**
	 * returns the current URL.
	 * 
	 * @return the current URL
	 */
	public String getURL() {
		m_URL = m_TextURL.getText();
		return m_URL;
	}

	/**
	 * sets the User.
	 * 
	 * @param user
	 *            the new value of the User
	 */
	public void setUser(String user) {
		m_User = user;
	}

	/**
	 * returns the current User.
	 * 
	 * @return the current user
	 */
	public String getUser() {
		return m_User;
	}

	/**
	 * sets the Password.
	 * 
	 * @param pw
	 *            the new value of the Password
	 */
	public void setPassword(String pw) {
		m_Password = pw;
	}

	/**
	 * returns the current Password.
	 * 
	 * @return the current password
	 */
	public String getPassword() {
		return m_Password;
	}

	/**
	 * adds the given string to the history (removes duplicates).
	 * 
	 * @param s
	 *            the string to add
	 */
	protected void addHistory(String s) {
		if (s.equals(""))
			return;

		// no duplicates!
		if (m_History.contains(s))
			m_History.removeElement(s);

		m_History.add(0, s);

		// send notification
		notifyHistoryChangedListeners();
	}

	/**
	 * sets the local history to the given one.
	 * 
	 * @param history
	 *            the history to use
	 */
	public void setHistory(DefaultListModel history) {
		int i;

		m_History.clear();
		for (i = 0; i < history.size(); i++)
			m_History.addElement(history.get(i));

		setButtons();
	}

	/**
	 * returns the history.
	 * 
	 * @return the current history
	 */
	public DefaultListModel getHistory() {
		return m_History;
	}

	/**
	 * displays the database dialog.
	 */
	protected void showDialog() {
		m_DbDialog = new DatabaseConnectionDialog(m_Parent, getURL(),
				getUser(), false);
		m_DbDialog.setVisible(true);
		if (m_DbDialog.getReturnValue() == JOptionPane.OK_OPTION) {
			setURL(m_DbDialog.getURL());
			setUser(m_DbDialog.getUsername());
			setPassword(m_DbDialog.getPassword());
		}

		setButtons();
	}

	/**
	 * connects to the database, notifies the listeners.
	 */
	protected void connect() {
		// disconnect if still connected
		if (m_DbUtils.isConnected()) {
			try {
				m_DbUtils.disconnectFromDatabase();
				notifyConnectionListeners(ConnectionEvent.DISCONNECT);
			} catch (Exception e) {
				e.printStackTrace();
				notifyConnectionListeners(ConnectionEvent.DISCONNECT, e);
			}
		}

		// connect
		try {
			m_DbUtils.setDatabaseURL(getURL());
			m_DbUtils.setUsername(getUser());
			m_DbUtils.setPassword(getPassword());
			m_DbUtils.connectToDatabase();
			notifyConnectionListeners(ConnectionEvent.CONNECT);
			// add to history
			addHistory(getUser() + "@" + getURL());
		} catch (Exception e) {
			e.printStackTrace();
			notifyConnectionListeners(ConnectionEvent.CONNECT, e);
		}

		setButtons();
	}

	/**
	 * displays the query history.
	 */
	public void showHistory() {
		JList list;
		ListSelectorDialog dialog;
		String tmpStr;

		list = new JList(m_History);
		dialog = new ListSelectorDialog(m_Parent, list);

		if (dialog.showDialog() == ListSelectorDialog.APPROVE_OPTION) {
			if (list.getSelectedValue() != null) {
				tmpStr = list.getSelectedValue().toString();
				if (tmpStr.indexOf("@") > -1) {
					setUser(tmpStr.substring(0, tmpStr.indexOf("@")));
					setURL(tmpStr.substring(tmpStr.indexOf("@") + 1));
					showDialog();
				} else {
					setUser("");
					setURL(tmpStr);
				}
			}
		}

		setButtons();
	}

	/**
	 * adds the given listener to the list of listeners.
	 * 
	 * @param l
	 *            the listener to add to the list
	 */
	public void addConnectionListener(ConnectionListener l) {
		m_ConnectionListeners.add(l);
	}

	/**
	 * removes the given listener from the list of listeners.
	 * 
	 * @param l
	 *            the listener to remove
	 */
	public void removeConnectionListener(ConnectionListener l) {
		m_ConnectionListeners.remove(l);
	}

	/**
	 * notifies the connection listeners of the event.
	 * 
	 * @param type
	 *            the type of the action, CONNECT or DISCONNECT
	 */
	protected void notifyConnectionListeners(int type) {
		notifyConnectionListeners(type, null);
	}

	/**
	 * notifies the connection listeners of the event.
	 * 
	 * @param type
	 *            the type of the action, CONNECT or DISCONNECT
	 * @param ex
	 *            an optional exception that happened (indicates failure!)
	 */
	protected void notifyConnectionListeners(int type, Exception ex) {
		Iterator iter;
		ConnectionListener l;

		iter = m_ConnectionListeners.iterator();
		while (iter.hasNext()) {
			l = (ConnectionListener) iter.next();
			l.connectionChange(new ConnectionEvent(this, type, m_DbUtils, ex));
		}
	}

	/**
	 * adds the given listener to the list of listeners.
	 * 
	 * @param l
	 *            the listener to add to the list
	 */
	public void addHistoryChangedListener(HistoryChangedListener l) {
		m_HistoryChangedListeners.add(l);
	}

	/**
	 * removes the given listener from the list of listeners.
	 * 
	 * @param l
	 *            the listener to remove
	 */
	public void removeHistoryChangedListener(HistoryChangedListener l) {
		m_HistoryChangedListeners.remove(l);
	}

	/**
	 * notifies the history listeners of the event.
	 */
	protected void notifyHistoryChangedListeners() {
		Iterator iter;
		HistoryChangedListener l;

		iter = m_HistoryChangedListeners.iterator();
		while (iter.hasNext()) {
			l = (HistoryChangedListener) iter.next();
			l.historyChanged(new HistoryChangedEvent(this, HISTORY_NAME,
					getHistory()));
		}
	}

	/**
	 * Called when the caret position is updated.
	 * 
	 * @param event
	 *            the event to process
	 */
	public void caretUpdate(CaretEvent event) {
		setButtons();
	}
}
